Re: [PATCH v3 10/15] efi_loader: net: add support to send http requests and parse http headers

Adriano Córdova
2024-11-13T14:02:52Z

El mar, 12 nov 2024 a las 10:51, Heinrich Schuchardt (<xypron.glpk@gmx.de>)
escribió:

> On 11.11.24 22:09, Adriano Cordova wrote:
> > Add network-stack agnostic way to send an http request and
> > parse http headers from efi drivers. This uses wget as a
> > backend and communicates with it via efi_wget_info.
> >
> > The function efi_net_do_request allocates a buffer on behalf of an
> > efi application using efi_alloc and passes it to wget to receive
> > the data. If the method is GET and the buffer is too small, it
> > re-allocates the buffer based on the last received Content-Length
> > header and tries again. If the method is HEAD it just issues one
> > request. So issuing a HEAD request (to update Content-Length) and
> > then a GET request is preferred but not required.
> >
> > The function efi_net_parse_headers parses a raw buffer containing
> > an http header into an array of EFI specific 'http_header' structs.
> >
> > Signed-off-by: Adriano Cordova <adrianox@gmail.com>
> > ---
> >
> > Changes in v3:
> > - Add a struct wget_http_info efi_wget_info for efi_net to pass to wget
> > when issuing wget requests, instead of using the old wget_info (see v2
> > of the series 'wget: Expose wget to applications').
> > - Let a pointer to the http status code be passed to efi_net_do_request
> > for it to fill it for the client after a request.
> >
> > include/efi_loader.h | 13 ++++
> > lib/efi_loader/efi_net.c | 158 +++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 171 insertions(+)
> >
> > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > index f49f8e6be0..4d05c08441 100644
> > --- a/include/efi_loader.h
> > +++ b/include/efi_loader.h
> > @@ -16,6 +16,7 @@
> > #include <image.h>
> > #include <pe.h>
> > #include <linux/list.h>
> > +#include <linux/sizes.h>
> > #include <linux/oid_registry.h>
> >
> > struct blk_desc;
> > @@ -136,6 +137,18 @@ void efi_net_get_addr(struct efi_ipv4_address *ip,
> > void efi_net_set_addr(struct efi_ipv4_address *ip,
> > struct efi_ipv4_address *mask,
> > struct efi_ipv4_address *gw);
> > +efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method,
> ulong *buffer,
> > + u32 *status_code, ulong *file_size, char
> *headers_buffer);
> > +#define MAX_HTTP_HEADERS_SIZE SZ_64K
> > +#define MAX_HTTP_HEADERS 100
> > +#define MAX_HTTP_HEADER_NAME 128
> > +#define MAX_HTTP_HEADER_VALUE 512
> > +struct http_header {
> > + uchar name[MAX_HTTP_HEADER_NAME];
> > + uchar value[MAX_HTTP_HEADER_VALUE];
> > +};
> > +
> > +void efi_net_parse_headers(ulong *num_headers, struct http_header
> *headers);
> > #else
> > static inline void efi_net_set_dp(const char *dev, const char *server)
> { }
> > static inline void efi_net_get_dp(void **dp) { }
> > diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> > index d4570d4d7c..30234ae1c7 100644
> > --- a/lib/efi_loader/efi_net.c
> > +++ b/lib/efi_loader/efi_net.c
> > @@ -17,6 +17,7 @@
> >
> > #include <efi_loader.h>
> > #include <dm.h>
> > +#include <linux/sizes.h>
> > #include <malloc.h>
> > #include <vsprintf.h>
> > #include <net.h>
> > @@ -34,6 +35,12 @@ static int rx_packet_num;
> > static struct efi_net_obj *netobj;
> > static struct efi_device_path *net_dp;
> >
> > +static struct wget_http_info efi_wget_info = {
> > + .set_bootdev = false,
> > + .check_buffer_size = true,
> > +
> > +};
> > +
> > /*
> > * The notification function of this event is called in every timer
> cycle
> > * to check if a new network packet has been received.
> > @@ -1003,6 +1010,10 @@ out_of_resources:
> > return EFI_OUT_OF_RESOURCES;
> > }
> >
> > +/**
> > + * efi_net_set_dp() - set device path of efi net device
> > + *
> > + */
> > void efi_net_set_dp(const char *dev, const char *server)
> > {
> > if (!strcmp(dev, "Net"))
> > @@ -1011,6 +1022,10 @@ void efi_net_set_dp(const char *dev, const char
> *server)
> > net_dp = efi_dp_from_http(server);
> > }
> >
> > +/**
> > + * efi_net_set_dp() - get device path of efi net device
> > + *
> > + */
> > void efi_net_get_dp(void **dp)
> > {
> > if (!net_dp)
> > @@ -1019,6 +1034,10 @@ void efi_net_get_dp(void **dp)
> > *dp = efi_dp_dup(net_dp);
> > }
> >
> > +/**
> > + * efi_net_get_addr() - get IP address information
> > + *
> > + */
> > void efi_net_get_addr(struct efi_ipv4_address *ip,
> > struct efi_ipv4_address *mask,
> > struct efi_ipv4_address *gw)
> > @@ -1068,6 +1087,10 @@ void efi_net_get_addr(struct efi_ipv4_address *ip,
> > #endif
> > }
> >
> > +/**
> > + * efi_net_set_addr() - set IP address information
> > + *
> > + */
> > void efi_net_set_addr(struct efi_ipv4_address *ip,
> > struct efi_ipv4_address *mask,
> > struct efi_ipv4_address *gw)
> > @@ -1117,3 +1140,138 @@ void efi_net_set_addr(struct efi_ipv4_address
> *ip,
> > memcpy((void *)&net_netmask, (void *)mask, 4);
> > #endif
> > }
> > +
> > +/**
> > + * efi_net_set_buffer() - allocate a buffer of min 64K
>
> Please, describe the parameters.
>
> > + *
> > + */
> > +static efi_status_t efi_net_set_buffer(ulong *buffer, ulong size)
>
> Please, use size_t for sizes.
>
> All invocations use size = 0. So we should drop the parameter.
>

Some invocations still use it

> +{
> > + efi_status_t ret = EFI_SUCCESS;
> > +
> > + if (size < SZ_64K)
> > + size = SZ_64K;
> > +
> > + efi_free_pool((void *)*buffer);
> > +
> > + *buffer = (ulong)efi_alloc(size);
>
> efi_alloc() returns a pointer.
>
> There is no good reason to store pointers in ulong. Please, use void *
> for pointers.
>

Makes sense, I will change it. But wget uses ulong for now, so I still cast
to ulong before calling wget.

> Patch 13/15 shows the resulting confusion:
>
> In efi_http_send_data() you assume http_load_addr is a sandbox virtual
> address:
>
> ptr = map_sysmem(inst->http_load_addr + inst->current_offset,
> transfer_size);
>
> And a few lines below you assume that it is a pointer:
>
> efi_free_pool((void *)inst->http_load_addr);
>
> We should keep sandbox specific addresses which need map_sysmem() and
> map_to_sysmem() out of the EFI implementation as far as possible.
>
> So let parameter buffer be of type **void here.
>
> We need a test that we can run both on the sandbox and on Q
>
> > + if (!*buffer)
> > + ret = EFI_OUT_OF_RESOURCES;
> > +
> > + efi_wget_info.buffer_size = size;
> > + //debug("efi_net: set buffer of size %lu at %lu\n", size, *buffer);
>
> It would be fine to have a debug statement here but, please, remove
> lines that only where used during your development process.
>
> Nits:
> As described in doc/develop/codingstyle.rst:224:
>
> "* Put a blank line before the last ``return`` in a function unless it
> is the only line:"
>
> > + return ret;
> > +}
> > +
> > +/**
> > + * efi_net_parse_headers() - parse HTTP headers
> > + *
> > + * Parses the raw buffer efi_wget_info.headers into an array headers
> > + * of efi structs http_headers. The array should be at least
> > + * MAX_HTTP_HEADERS long.
>
> Please, describe the parameters.
>
> > + */
> > +void efi_net_parse_headers(ulong *num_headers, struct http_header
> *headers)
> > +{
> > + if (!num_headers || !headers)
> > + return;
> > +
> > + // Populate info with http headers.
> > + *num_headers = 0;
> > + const uchar *line_start = efi_wget_info.headers;
> > + const uchar *line_end;
> > + ulong count;
> > + struct http_header *current_header;
> > + const uchar *separator;
> > + size_t name_length, value_length;
> > +
> > + // Skip the first line (request or status line)
> > + line_end = strstr(line_start, "\r\n");
> > +
> > + if (line_end)
> > + line_start = line_end + 2;
> > +
> > + while ((line_end = strstr(line_start, "\r\n")) != NULL) {
> > + count = *num_headers;
> > + if (line_start == line_end || count >= MAX_HTTP_HEADERS)
> > + break;
> > + current_header = headers + count;
> > + separator = strchr(line_start, ':');
> > + if (separator) {
> > + name_length = separator - line_start;
> > + ++separator;
> > + while (*separator == ' ')
> > + ++separator;
> > + value_length = line_end - separator;
> > + if (name_length < MAX_HTTP_HEADER_NAME &&
> > + value_length < MAX_HTTP_HEADER_VALUE) {
> > + strncpy(current_header->name, line_start,
> name_length);
> > + current_header->name[name_length] = '\0';
> > + strncpy(current_header->value, separator,
> value_length);
> > + current_header->value[value_length] = '\0';
> > + (*num_headers)++;
> > + }
> > + }
> > + line_start = line_end + 2;
> > + }
> > +}
> > +
> > +/**
> > + * efi_net_do_request() - issue an HTTP request using wget
>
> Please, complete the function description.
>
> > + *
> > + */
> > +efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method,
> ulong *buffer,
>
> Please, use void **buffer. Below you are assuming *buffer is a pointer
> and not a sandbox virtual address.
>
> > + u32 *status_code, ulong *file_size, char
> *headers_buffer)
> > +{
> > + efi_status_t ret = EFI_SUCCESS;
> > + int wget_ret;
> > + static bool last_head;
> > +
> > + if (!buffer || !file_size)
> > + return EFI_ABORTED;
> > +
> > + efi_wget_info.method = (enum wget_http_method)method;
>
> Parameter method has type 'enum wget_http_method'. Please, remove the
> superfluous conversion.
>
> Parameter has type efi_http_method (efi_api.h), not wget_http_method
(net-common.h). These enums are the
same, I didn't want to expose the efi api to wget, but I could.

> Best regards
>
> Heinrich
>
> > + efi_wget_info.headers = headers_buffer;
> > +
> > + switch (method) {
> > + case HTTP_METHOD_GET:
> > + ret = efi_net_set_buffer(buffer, last_head ?
> efi_wget_info.hdr_cont_len : 0);
> > + if (ret != EFI_SUCCESS)
> > + goto out;
> > + wget_ret = wget_request((ulong)*buffer, url,
> &efi_wget_info);
> > + if ((ulong)efi_wget_info.hdr_cont_len >
> efi_wget_info.buffer_size) {
> > + // Try again with updated buffer size
> > + ret = efi_net_set_buffer(buffer,
> (ulong)efi_wget_info.hdr_cont_len);
> > + if (ret != EFI_SUCCESS)
> > + goto out;
> > + if (wget_request((ulong)*buffer, url,
> &efi_wget_info)) {
> > + efi_free_pool((void *)*buffer);
> > + ret = EFI_DEVICE_ERROR;
> > + goto out;
> > + }
> > + } else if (wget_ret) {
> > + efi_free_pool((void *)*buffer);
> > + ret = EFI_DEVICE_ERROR;
> > + goto out;
> > + }
> > + // Pass the actual number of received bytes to the
> application
> > + *file_size = efi_wget_info.file_size;
> > + *status_code = efi_wget_info.status_code;
> > + last_head = false;
> > + break;
> > + case HTTP_METHOD_HEAD:
> > + ret = efi_net_set_buffer(buffer, 0);
> > + if (ret != EFI_SUCCESS)
> > + goto out;
> > + wget_request((ulong)*buffer, url, &efi_wget_info);
> > + *file_size = 0;
> > + *status_code = efi_wget_info.status_code;
> > + last_head = true;
> > + break;
> > + default:
> > + ret = EFI_UNSUPPORTED;
> > + break;
> > + }
> > +
> > +out:
> > + return ret;
> > +}
>
>